Nuclear proteome analysis of apple cultivar ‘Antonovka’ accessions in response to apple scab ( Venturia inaequalis )

This study presents the first comprehensive description of the differential nuclear proteome of apple leaves during the interaction with the fungal pathogen Venturia inaequalis . Nuclear proteins isolated from V. inaequalis infected leaves of three different apple genotypes, two ‘Antonovka’ accessions of varying resistance and cultivar ‘Puikis’ used as a control, were subjected to 2DE-DIGE. The analysis of proteins revealed 186 protein spots with significant differences in protein abundance ( P ≤ 0.01), of which 67 proteins were identified through LC-MS/MS analysis. The proteins were classified into 9 functional categories that included redox regulation, cell signalling, cell homeostasis, protein degradation, epigenetic control, energy metabolism, photosynthesis, other stress-related proteins and proteins with unknown biological function. Comparison of the ‘Antonovka’ accessions revealed 13 proteins with different expression patterns. Among these were proteins mainly involved in ROS scavenging mechanisms, ubiquitin/26S proteasome-mediated protein degradation, protein folding and carbohydrate metabolism that may contribute to a varying resistance of ‘Antonovka’ accessions to apple scab. These results provide novel insights into the response of apple leaves to fungal pathogen infection and promote further investigation of the molecular mechanisms of apple resistance to V. inaequalis .